1) Inflatable dart board.

2) Glow-in-the-dark sunglasses.

3) A book on how to read.

4) Solar-powered flashlight.

5) Screen door on a submarine.

Damn! Back to the drawing board

Ha! I remember back in the late 80s when Acid House & Rave was the latest scene, loads of people wore glow in the dark sunglasses. I preferred my white gloves.
Big Fish, Little Fish, Cardboard Box....

Here's a link to a web page with lots more useless inventions :

http://winn.com/bs/invent.html